Cmon..be serious?
Steam Keygen?
Lolno.
If there was one, we could generate Steam keys and the whole point of Steam would be lost..So obv, there isn't any, REAL one.
And yea, I'm pretty sure that you got RAT-ed/Keylogged because of that "MW4" keygen..
If you want to play the game for free, use either Reacted or PlusOps2 client.